My last question got put on hold for being too broad (you can see it here) so I decided to chop it up into a couple smaller, more manageable questions. I explained the scenario I'm working with in the old question but I'll go ahead and put it in a quote here.

I would like to make a world that follows all of our laws of physics except that every star has a habitable, earth-like planet in its Goldilocks Zone (I love that term). Each planet has a collection of plant and animal life that is almost identical to ours and a single humanoid immortal.

The immortals are just like us in all appearances and fitness. Some of them look male and some look female but due to their immortality they can't reproduce. They can be wounded, but heal very quickly (like regrowing a limb overnight kind of quickly). They cannot be killed but can get "stuck." Getting "stuck" happens when they get put in a situation that would kill a human but, for whatever reason, they can't heal from it. A good example of this is drowning, they can't breath so their brain gets shut down and if they can't float back to the surface on their own, they will be considered "stuck" until they can resurface.

Each immortal has his own planet and starts out with a basic understanding of their world. They know they can get "stuck," They know what a tree is, and they know how to walk and move with basic agility as well as decent abstract and concrete reasoning skills.

My question here is: in general, about how long would it take for a given immortal to stabilize himself and stop worrying about food and shelter?

The reason I ask this is because in the old question it came down to each immortal eventually having enough food and shelter, not having to worry about getting more, and sit down to relax the eons away. Personally, I think that they will all get bored of this eventually and start innovating, but that is for a later question.

EDIT FOR CLARIFICATION: they do need to eat. After a while, they will begin to feel hungry like we do. It will grow steadily worse until it starts to make them very weak. In the end they will barely be able to crawl. Hunger is another way they can end up "stuck."

  • $\begingroup$ Do they even need to eat, considering they are immortal? $\endgroup$ Commented Feb 13, 2016 at 5:24
  • $\begingroup$ @2012rcampion they do need to eat. I'll edit why into the question. $\endgroup$
    – unknown
    Commented Feb 13, 2016 at 9:30
  • $\begingroup$ Do the worlds have Earth-life? $\endgroup$
    – TrEs-2b
    Commented Feb 13, 2016 at 9:51

1 Answer 1


The time it takes them to build/find a shelter depends primarily on:

The Environment

In mountainous terrain, it is easy to find pits, caves and gorges which the immortal can call home and settle in. In such regions, the immortal would gradually forsake the lower dwellings for a large underground cavern which protects him/her from the fury of nature (storms, hurricanes, landslides etc) and enables him a place for storing food.

In a jungle or lake habitat, the immortal would need to build cabins or dig deep pits in the ground and roof them up in order to make a secure underground dwelling.

Personal Strength And Mental Abilities

What if such caverns are already home to other (vicious) creatures such as tigers, bears, sabretooths (if you start them in prehistoric times)? Well it depends on you if the immortal can kill them or chase them away from such a hospitable place.


How long would it take the immortal to claim a suitable cavern or build a cabin/hut, you ask. Well it depends heavily on the physical strength of the immortal, his/her innovation and intellect. For example, a strong male immortal knowing the use of fire can chase away a pair of cave bears from a comfortable cavern while an immortal woman with strength equal to modern Asian women, not knowing the use of fire would find it impossible to even chase away a tiger from such a cavern.

With the strength and intelligence of a 20 years old person in our times and knowing very well what they require, have primitive woodcutting tools and are convenient with the use of fire, an immortal would take nearly 6 months to find and claim a cavern or build a rudimentary shelter in jungle/plains habitat.

Hunting Tools

The first stage of food awareness would be to learn which plants are edible and which are not. The next stage would be to learn which animals (including fish and birds) are edible. At this stage the immortal would primarily be a scavenger, feeding off scraps left by carnivores. As the knowledge of the immortal grows and his/her tool-making skills evolve, he/she will learn how to make rudimentary spears, and then (after several years) a primitive type of lance and archery equipment. He/She may also discover making blowpipes (provided the habitat has a lot of bamboo trees with long, straight stems).

Now we have an immortal who can hunt, fish and knows which plants to consume. How long would it take the immortal to reach this stage? Well, once again it depends on the innovation of the immortal, the habitat and the physical skills. For example, a strong male immortal with strength comparable to African males would probably be stuck with spear as the main offensive/defensive weapon and not invest time and energy in figuring out how to build a projectile weapon (bows and blowpipes) because the spear serves his needs very well. On the contrary, an immortal woman would quickly quit the spear in search of a weapon which she can use from range, hence forcing her to invent blowpipe or archery. For a 20 years old modern human, it would only take a day to start using a stick, a week to start sharpening one end for use as a spear and around 2-3 years to build primitive blowpipes or archery set.

Food Storage

Some environments allow for easy food storage. For example, in cold regions such as the arctic belt, you only need to bury your kill in snow to keep it from rotting. In warmer regions such as Africa and South Asia, you will require salting and sun-drying the meat to keep it from rotting. The same applies to storing seasonal fruits such as mango, apples etc. The immortal would strongly prefer storing dry fruits for their easy storage options. How long would it take for an immortal to discover food storage methods in warmer regions such as Africa? Well ... once again it depends heavily on the innovation and intellect of the immortal along with chance occurrences and luck. Maybe the immortal one day sees a dead deer in a pit on the coast line, buried in deposited sea-salt and finds out that its meat has not rotten. Maybe the immortal learns pickling methods from birds?


It is extremely hard to tell how long would it take the immortal to come up with the idea of growing edible plants as a food source. Maybe a very innovative and resourceful immortal gets the idea in the 20th year of his life. Maybe he never hits upon that idea. There are simply too many factors involved to sort this one out.

Herding Animals

Herding deer, goats, reindeer, camels, cows etc for food and milk is another idea which is very hard to tell if and when the immortal would hit upon. I personally think that while the immortal might discover agriculture ideas someday, it would be impossible for him/her to get the notion of herding animals and domesticating them. Why? Simply because the immortal has limited experiences and limited resources. He has always experienced that the deer and other herbivores would run away when he approaches them. What on earth would make him conceive the idea that he can gradually (over a period of hundreds of years) domesticate them? I think such a stage would never be achieved.

Domesticating Dogs/Tigers

This is actually easier than domesticating cattle and/or horses. Carnivores have lesser fear of man and if you keep feeding them, you can get them to get used to your presence. At first stage there would be a mutual bond of not harming each other (notice that this bond is formed between one dog/tiger and the immortal, not a group of them). The next stage would ensue, where the immortal feeds scraps of his food to the animal and trust gradually grows between them. In the third stage, the immortal and the carnivore would gradually come closer and be joined in a bond of loyalty and care. This is when the carnivore can be said to be truly domesticated.

Once a carnivore has been domesticated, the immortal can use it to gain a huge edge at hunting. But how long would it take for such a bond to form? Once the first stage has been reached (a silent agreement of not hurting each other), the rest would gradually follow. I would say that it would take the immortal around 30 years to gradually domesticate a wolf or tiger. At the first stage, there would be an animal which shares a pact of peace and its generations would gradually follow on to progress to second and third stages where they are convenient about hunting with the immortal as their pack member. Once such a stage has been reached, the immortal would have an easy supply of food.


All in all, the immortal would take nearly 40 years to reach a state where he/she has no longer to worry about food and shelter and can think about abstract ideas and start an effort to understand the world around him/her.

  • $\begingroup$ Great answer! This is exactly what I was looking for. $\endgroup$
    – unknown
    Commented Feb 13, 2016 at 16:54

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